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The aim of this paper is to evaluate dynamic infrared thermography (DIRT) as a technique to assist in preoperative perforator selection and planning of free deep inferior epigastric perforator (DIEP) flaps. Twenty-seven patients, scheduled for secondary autologous breast reconstruction with either a free DIEP flap or superficial inferior epigastric artery flap, were included in this prospective clinical study. Preoperative mapping of perforators was performed with a hand-held Doppler and DIRT. A multidetector computer tomography scan was additionally carried out in the last 8 patients. In 23 patients a DIEP flap was used. The perforator as selected from DIRT was a suitable perforator in all DIEP flaps. The location and quality of the selected perforator from DIRT corresponded well with the multidetector computer tomography scan results. Preoperative perforator selection and planning of DIEP flaps is facilitated with the use of DIRT. The technique is noninvasive and easy to use.

Flap failure in free-tissue transfer relates strongly to technical failure of the anastomosis or to kinking as well as to external compression of the donor or recipient vessels. Intraoperative monitoring of flap perfusion has shown to prevent flap failure. This prospective, clinical study presents the results of intraoperative dynamic infrared thermography as a novel method to monitor reperfusion indirectly in 10 free flaps. This noninvasive technique provided a fast and reliable method to register partial or total arterial occlusion due to anastomotic failure, as well as due to external compression or kinking of the vessels. The dynamic infrared image sequences showed an improved rate and pattern of rewarming of the flap after an additional venous anastomosis was opened. The state of reperfusion of the flap at the end of the operation could easily be determined. The authors conclude that dynamic infrared thermography provides the surgeon with valuable information on flap reperfusion during free flap surgery.

BackgroundThe current gold standard for preoperative perforator mapping in breast reconstruction with a DIEP flap is CT angiography (CTA). Dynamic infrared thermography (DIRT) is an imaging method that does not require ionizing radiation or contrast injection. We evaluated if DIRT could be an alternative to CTA in perforator mapping.MethodsTwenty-five patients scheduled for secondary breast reconstruction with a DIEP flap were included. Preoperatively, the lower abdomen was examined with hand-held Doppler, DIRT and CTA. Arterial Doppler sound locations were marked on the skin. DIRT examination involved rewarming of the abdominal skin after a mild cold challenge. The locations of hot spots on DIRT were compared with the arterial Doppler sound locations. The rate and pattern of rewarming of the hot spots were analyzed. Multiplanar CT reconstructions were used to see if hot spots were related to perforators on CTA. All flaps were based on the perforator selected with DIRT and the surgical outcome was analyzed.ResultsFirst appearing hot spots were always associated with arterial Doppler sounds and clearly visible perforators on CTA. The hot spots on DIRT images were always slightly laterally located in relation to the exit points of the associated perforators through the rectus abdominis fascia on CTA. Some periumbilical perforators were not associated with hot spots and showed communication with the superficial inferior epigastric vein on CTA. The selected perforators adequately perfused all flaps.ConclusionThis study confirms that perforators selected with DIRT have arterial Doppler sound, are clearly visible on CTA and provide adequate perfusion for DIEP breast reconstruction.Trial registrationRetrospectively registered at ClinicalTrials.gov with identifier NCT02806518.